You can get infinite extra lives by getting the 1-up's here in the honeycomb level and dying on the wall behind them. The closest checkpoint is around 20 secs prior to this point so it's really efficient!
Post
I found a much more efficient spot, you can get the lives immediately upon respawning. Only downside is you have to listen to Om-Nom repeatedly say: "Oh no, he's gonna make me look bad, I mean worse!"
